1. Field of the Invention
The present invention relates to a compressor used for an air conditioning system for a vehicle, and more particularly to a single-headed piston type compressor having a structure of reducing the pulsation pressure of discharged gas.
2. Description of the Related Art
In general, in an air conditioning system for a vehicle, noises are generated due to pressure pulsation of sucked or discharged gas. In order to reduce a noise generated due to pressure pulsation of the discharged gas, conventionally, a separate discharge muffler chamber has been provided on the outer circumferential surface of a compressor. In this case, however, the overall volume of the compressor is undesirably increased, so that the compressor cannot be suitably used for vehicles which require a small, lightweight compressor. Also, in this case, it is necessary to install a connecting passage that connects a discharge chamber inside a rear housing with a discharge muffler chamber provided on the outer circumferential surface of the compressor. Thus, as the length of the passage increases, a reduction in the amount of compressed refrigerant is increased, thereby lowering the performance of the compressor.
To overcome the above-described problem, there has been proposed a compressor, as shown in FIGS. 1 and 2 in which only a suction muffler chamber 6 connected to an external refrigerant circuit through a suction port 6a is formed on the outer circumferential surface of a cylinder 2, but a discharge muffler chamber is not formed. Here, refrigerant gas of a discharge chamber 7 is discharged through a discharge pipe 3 formed in the rear portion of a rear housing 1. In this case, since distances L1˜L6 (FIG. 2) between discharge holes 8 each connecting the cylinder 2 with the discharge chamber 7 and an inlet 3a of the discharge pipe 3 are different, pressure pulsation of the refrigerant gas discharged at each of the respective discharge holes 8 is different from the pressure pulsation of the refrigerant gas discharged at the inlet 3a of the discharge pipe 3. Thus, the overall pressure pulsation is not reduced.
To solve the above-described problem, as disclosed in U.S. Pat. No. 6,568,914 to the applicant of the present invention, at least two discharge holes are formed at a discharge pipe so as to allow a predetermined phase difference at a position where refrigerants induced to a discharge pipe passage through the two discharge holes, meet, thereby minimizing an increase in pulsation pressure. In order to allow a predetermined phase difference between the respective refrigerants induced to a discharge pipe passage through the two discharge holes, the number, size, and position of each of the discharge holes should be determined theoretically or by a trial-error method, which is, however, not easy to carry out in practice.